Hey guys just wondering if anybody knows why when Im on the hiway say going 65 or 70 and I let off the gas my cutlass seems to make a popping or kind of backfire noises....I know its not back fire the RPM's are over 3000, When I put my headers on and had open headers going to mufller shop I could hear it worse then i got pipes welded to collectors and know still hear it but not as bad as with open headers.Any suggestions thanks

 

It's exhaust gasses re iginting as they are exposed to oxygen nothing bad. This is what i was told atleast years ago.

 

I have a similar "problem" Many told me it might be a rich condition with the carb. I leaned it out, the noise went away, but it seemed to no have as much pick me up after say 35mph.

 

What do you mean by "leaned out" settings?

 

Sorry, on my edelbrock 1406 carb, there are two idle mixture screws. I turned them both in about 1/2 a turn. The popping stopped almost completely. At 80mph at WOT if I let off completely, it would pop a couple of times and stop. I assume thats normal.

But again, leaning the car out like that did negate performance around 30-35mph. Second gear didn't seem to have the same pull, so I turned them back out.

I may have a slew of other problems, but this happened to me. Maybe someone else can explain as to why.

 

Leaning the idle air/fuel mixture will have no effect on your performance off idle. So you have another problem.

As copper said, it's normal, unles it's a very loud backfire. Hi flow exhaust are a bit noisier than stock.

 

When you let off the gas completely while doing 65 it would have an affect. Mine would only pop if I cruising and completely let off.

But granted the other problem is not related and relates to another cause.